Look for pkg-descr in Attic, if it can not be found in the expected
directory.

This fixes the problem reported several times on www@ when a port's
pkg-descr file is CVS deleted and INDEX isn't fully updated, then the
description link in ports.cgi will not work, because url.cgi can't the
pkg-descr file.

PR: www/53386
Submitted by: myself
Approved by: ceri (mentor)